]> Hello, In the article "Many Holes in Hindley-Milner" [1], Sam Lindley claims that the type of x is ('a * 'a s, int) NList.t in the following ocaml program because of Garrigue's relaxed value restriction [2]. ========== type 'a s module NList : sig type (+'length, +'elem_type) t val nil : ('m*'m, 'a) t val cons: 'a * ('m*'n, 'a) t -> ('m*'n s,'a) t end = struct type ('i,'a) t = 'a list let nil = [] let cons (x, l) = x :: l end let x = NList.cons (1, NList.nil) ========== But, both with ocaml v3.10.2 and ocaml v3.12.0+dev1 (2008-12-03) (that is the current cvs version), the infered type of [x] only contains a weak type variable: ('_a * '_a s, int) NList.t. I quickly look at the typing rules introduced by Jacques Garrigue in [2] and it seems to me that Sam Lindley is right: [x] is generalisable in the above program. So, what's wrong here? [1] Many Holes in Hindley-Milner. Sam Lindley. In ACM Sigplan Workshop of ML 2008, Victoria, British Columbia, Canada, September 2008. [2] Relaxing the value restriction. Jacques Garrigue. In International Symposium on Functional and Logic Programming, Nara, April 2004. Springer-Verlag LNCS 2998. Best regards, Julien Signoles -- Researcher-engineer CEA LIST, Software Reliability Lab 91191 Gif-Sur-Yvette Cedex tel:(+33)1.69.08.71.83 fax:(+33)1.69.08.83.95 Julien.Signoles@cea.fr